P460NL1钢制球罐焊后消除应力退火工艺研究

Post-weld Stress Relief Annealing of Steel P460NL1 Spherical Tank

通过热模拟方法使试样获得焊接热影响区的粗晶组织 ,然后将模拟试样加工成标准夏氏冲击试样 ,经 5 0 0、5 2 0、5 5 0、5 80、6 0 0、6 2 0、6 5 0℃等 7个不同温度进行去应力退火。通过对冲击试样所做的冲击韧度的测定 ,金相组织的观察以及配合断口扫描与探针分析 ,发现该钢在 5 80～ 6 0 0℃温度区间存在再热脆化的倾向。经试验测定和分析认为 ,在 5 5 0± 15℃温度下进行去应力退火 ,可有效地去除残余应力 ,并能保证各项力学性能指标符合设计要求。

The coarse grained structure of heat affected zone(HAZ) was gained through the thermal simulating method.After thermal simulation,the samples were cut into standard Charpy V impact samples,then annealed at different temperatures (500℃?520℃?550℃?580℃?600℃?620℃ and 650℃ respectively) to relief residual stresses.The results show that the temper embrittlement exists in steel P460NL1 after post weld heat treatment between 580℃ and 600℃ by measuring the impact toughness,observing the optical microstructure,SEM analyzing and electron probe micro analyzer.It is effective to be annealed under 550℃±15℃ for relieving residual stresses,and can ensure requirement of the mechanics properties.